The maximum entropy approach is one of the most important threshold selection methods. Many authors avoid the computationally prohibitive problem when the maximum entropy criterion is applied to multi-level threshold selection. This paper deals with this problem using ICM method. Experiments show ICM can get satisfactory if not optimal results using our initialization algorithm and solve the problem of computation excellently. Also in this paper, we have modified the fuzzy maximum entropy criterion of Cheng et al. In addition, we compared our ICM method with the simulated annealing algorithm proposed by them.